I wanted to create another topic on this with a more direct title so that Blizzard sees this. There is another post on this, but more vaguely named, here: Switch: Failed to join game - Console Bug Report - Diablo 2 Resurrected Forums (blizzard.com)
Anyway, after patch 2.3 was applied, any offline character with 2 special characters in the name was made invalid and would receive the “Failed to join game” message when trying to load it. It was fixed a week or so after 2.3 was released.
However, the issue is back in 2.4. While it gives the message that the character’s name is invalid and gives us an opportunity to rename the character, no matter what I rename it to (even a name without any special characters), it still gets the “Failed to join game” message. Hopefully a fix is already in the works, but wanted to make sure this gets the visibility it needs.